Rotary blower impeller



Oct. 9, 1934- w VAN RIJSWIJK 1,975,911

ROTARY BLOWER IMPELLER Filed Feb. 23, 1932 .20 are constructed.

'a ten ted ct. 9, 1934 PTENIT OFFICE UNITED" S'TES ROTARY BLOWER IMPELLER.

Willem van Riiswjk, Barien, Switzerland, as-

sgnor to Aktiengesellschaft Brown Bpveri &

'Cie. Baen, Swiizzerland, a joint-steek company of Switzerlandl pplication February 23,1932, Serial N0. 594,458 In Germany February 23, 1931 9 Claims. (Cl; 170-173) This invention relates to improvements in rotary bi-owers or compressors and more particu- Lar1y to en improved construetien in the rotatirig member or impeller wheel for such blowers or compressors.

When the impeller wheels of rotary b1ovvers or compressors are provided with b1ades extending in a substantialiy radia1 direction relatve to the shaft en which such whee1s are mounted, the

blades and the hub of the whee1s may be made integral 01' the blades may be secured to the hub by any suitable type of fastening. In cases where phe wheels must be very light, the blades must be relatively thin. Such b1ades are, however, subjected to very high stresses in the circumferential direction When the speed of the wheel is ether .aecelerated or retarded and. may be easily caused to oscillate which causes breaking of the blades due 120 atigue f the material of which -the blades It is, therefore, among the objects of the present: invention to provide an impeller whee1 construction for 'rotary blowers or compressors in whieh the weight of the wheel is redirced by constructing the blades of sheet metalsecured to ihehub. Another object of the invention is to provide .an impeller whee1 construction for rotary blowers 01 compressors in which the blades are constructed of sheet metal and are individually seeured to the hub.

Another object of the invention is to provide an impeller whee1 for rotary blowers or compressors in which the several blades are constructed of several joned sheet meta1 portons individually secured to the hub.

A nother object of thenvention is te provide an impeller whee1 constructon for retary blowers or compressors in which the blades =are eo-nstructed, of severalsheet metal Portions individualy s0 secured to the hub as to av0iddiminishing the material at the perphery of the hub ancl henee thecrcumferential strength of the hub.

Objects and advahtages other than these abeve Fig. 2 is an illustration of theview shown in Fig. 1 taken at right angles co theshaft;

Fig. 3 is a modified embodiment of the inventionin a view simlar to that shown in Fig. 1 bu0 showing a difirent form of b1ade root 01 fastening with the hub frming aportion of the whee1;

Fig. 4 is a view of the illustraton shown in Fig. 3 taken at right angles to the shaft;

Fg. 5 is a view si-milar tethat shown in Figs.

1 and 3 of a modified embodiment of the invention in whch one edge of one of the portions forming the blades extends beyond the side of the hub 'and is curved to form a guide for the medium upon which the blower operates;

Fg. 6 is a view simiiar to that shown in Fig. 5 of a modified embodiment in which each of the portions forming ons b1ade have an edge thereof extending beyond the hub, wheh edges are curved to form a gude for the medium on which the blower operates and are joined at theeuter edge thereof;

Fig. '7 is a top view of the embodment shown in Fig. 5, taken on line 7-7 of Fig. 5; and.

Fig. 8 is a top view of the embodiment shown in Fig. 6, taken on line 8-8 of Fig. 6.

Referring moreparticularly to the drawing by characters of reference, the reference numeral 11 designates a portion of a shafton which any desired numberof impeller wheels aie to be mounted in a suitable marmer. Eaeh of the impeller whee1s comprises a hub 12 and a plurality of iblades formed of separate sheet metal portions 13 and 14: extendingin such marmer that the blades extend substantially radally from the hub re1ative to the shaft 11. The portions forming each blade are attached to each other by some suitable means such as welding 01 riveting and each of the blade' portions isindividually secured to the hub by means of a root member as shown at 16 and 17 n Fig. 1 er at 18 and 19 in Fig.

3, The root membrs are in the form either of rod-1ike: portions whch fit in close engagement nto groovs in: the hub or of quadrangular portionsforming, with smilarly shapedgrooves in the hub, dove-tailed jonts by whichthe b1ade portions are retained in the hub. Therootmembers may, of course be secured into thegrooves "by welding if desred. It will be seen in Fig.1

t hat the roet members 16 are on a different cir- C1e,re1ative to*the axis of the shat 11, from the circle on which the root members 17 are 10- catecl. The material removed from the hub to form the grooves which receive the root members is thus removed substantially uniformly throughout the entire mess of the hub and the tensile strength of the hub rema.ins constant throughout a11 portons thereof. Each of the blade portions, being at the same angle with the periphery of the hub, is stressed by the same amount and the complete blade is very rigicl a.s respects bendng on an axs a.t rght angles to the s.xis of the shaft. The several blade portons may thus be made very light whereby the likelhood of oscillations due to the 10W inertia of the blades and their corresponding high frequency sverymuch reduoed.

When a. relatvely small nunber of bl.des are to be arranged on ea.ch hub, the severalportions forming ea.ch blade may be formectwith the quadra:ngular root portions 18 and 19 engaging in similar quadrangular grooves formed inthe periphery of the hub 12 in suchmannervas to form a dove-tailed joint. The grooves are all at the same depth from the periphery of the hub-anol-the por-tions 13 and 14 areall of thesame length and the portions formng eachblade are .joined. It will be seen, consdrng center =1nes taken radially of the hubs through the grooves, that the spa.oing of the blade roots inthe em- -bodimentshown in Fig. 3 is the same or greater than the spa'.cng of the bla.de roots shown in Fig. 1. The amount of materi al rema.ining in the periphery of the hub is thereforsuficent to prevent overstressing -theref. The number of blades=which ma.y bemounted. on the hubs of -samesi2e by the difierent types of mountings a.bove described is, however, 1ess in the form -shown in=Fig. 3 than in the form shownin Fig.

1 due to the requirement or suflcent tensile strength in the hub at the perphery thereof.

Under soms conditons of operations, t is desirable to provide the blades with an nlet lip or edge which will sid. in guidng the air or other medium operated. upon by the blower into the blades. Figs. 5 and 7 illustrate oneembodiment of the invention in which only the b1a.de portion 1 1 whichis :directly contact with the-medium handledby the blower is .p rovidedwth the lip 01' guidingedge2l. The guding edge is curved on the most desirable curve to secure the maximum de1 ivery of airto the front of the blade ;1aorton 14. Theguiding edge need'not extend over thefll 1ength of the. b1ade but may be restricted to the 1ength of theblade over which the gas is actually entering. T0 secure the maximum rgiclty of the blades, and particula'rly oftheinlet or guiding edges there0f, tis.preferab1e that the rea.r portionl3 of eajch b1a.de be els0extended beyond thehub.asindicated at 22 and be curved in sueh manner-as tobe capable of .joning with the guiding edge21toorm a reinforced-guiding edge or the entire b1ade.

The prsentinvention proVdesa. blade construction for rotary blowers or compressors in Which the severahportons forming each b1ade "renforce each other and avoici the producton of excessivestresses in the b1ade upon change in speed of the blower. Osii1ations ofth b1ade are e lso verymuchrduced by the presentconstrction thusavoiding breakage of the b1acles due to fatigue.

Although butafew embodiments of the present inventon-have been illustratedand described, t wl1 beapparentto those-sklled in the art tha.t varousgchanges end modificationsmay be made therein without departing from the spirit of the invention or from the scope of the appended claims.

It is cla.med and desired to secure by Letters Patent:

1. An mpeller whee1 fox rota.ry blowers or compressors comprising 2. hub, and a plurality of -b1aeles extencling therefrom, each of said blades beng formeel from two portons joined .1ong an edge thereof and beng attached to said.

hub.

2. An impeiler wheel fox rotary blowers or compressors comprising a hub, and a plurality of blades extendngin a substantially radial drectiontherefrom, each of sa.d b1a.des being formedfrom two portions joined. along an edge thereof an'd being securecl to said hub, the blacle portons being substantially straight.

3. An mpel1er wheel fo1 rota.ry blowers or compressors comprsing a. hub, and a plurality of blades extending therefrom, each of sad. bladesbeing formeel from two portons immoven edge thereof and 'extending t0 unequal depths into said hubfor a.ttachment thereto.

6."An m'pe'ller wheel for Tota.ry blowers '01 compressors comprising a. hb, and aplur.lty of blades extendingtherefrom,each of saidbldes being formed from two portohsjoined 'long en {1:15

edge thereof and beng attached to said hub.one of the bladeportions havingan e'c1ge thereof extending beyondan edge0f sadhub to form a, operated on: bythe blower.

compressors comprising a hub, and a plurailitybf being ormed rom two portions joined along en edge thereof and being 'atta'hed to said hub,

beyond an edge of said hub toforma. guide3for a. medium to beoperated onby theblower.

8. An impeller wheel for rotary "blowersor compressors comprising a hub, and a. pluralty of blades extending therefrom, ea'ch of said"blades being formed from two portions imnovably joined along en edge thereof and extendng to -unequal depths into sadhub for ndividualattachment thereto.

9. An impeller wheel jfor"rotary blowers -or" compressors combrisihgahub, andablura.lity of b1adesextending 'therfrom, "each of sa.id blades being formed from two" portons =immovably joined a.1ong an edge thereof and. extending to tachment thereto, the b1ade portions havng -joineo edges extending. beyondthe edge of=sa.id

hub to form a. guide forar-mediumto-becompressed by the blower.

WILLEM VAN RIJSWIJK.

7.An mpeller wheeifor rotary"blowers or the biadeportons having jonededges'extending 5125 

